Fig. 1: Primary cilia sense nutrient availability.
From: Primary cilia sense glutamine availability and respond via asparagine synthetase
a, Representative fluorescence images of MEFs stably expressing ARL13B-GFP, and IF images of hRPE, mIMCD3 and MDCK cells in the indicated culture conditions. Cilia (ARL13B, green), nuclei (DAPI, blue). Scale bar, 5 µm. b, Top: quantification of cilia length in one representative experiment in the indicated cell lines in nutrient-rich (DMEM or DMEM/F12 ± 10% FBS) or deprived (HBSS) medium. n indicates number of cilia whose length was measured in the same representative experiment in the indicated cell line. Bottom: percentage (%) of ciliated cells of one representative experiment in the same conditions. n indicates cilia percentage in three different wells per condition of the same representative experiment. c, Experimental design of NMR spectroscopy on MEFCtrl (CT) and MEFIft88 (KO) conditioned medium after 24 h culture in DMEM + 0% FBS. d, Hierarchical clustering of extracellular metabolites assessed by NMR spectroscopy as in c. e, Box-and-whisker plots of the levels of glutamine and glucose uptake, glutamate and lactate production in MEFCtrl (CT) and MEFIft88 (KO) cells assessed by NMR spectroscopy as in c, n = 5 biological replicates. f, Quantification of cilia length in one representative experiment in MEFs and hRPE in HBSS ± d-(+)-glucose (Glc) (20 mM) or l-glutamine (Q) (4 mM). n indicates cilia length measured in the same representative experiment. g, Schematic representation of glutamine utilization for OXPHOS. h, Left: analysis of OCR measurement of one representative experiment in MEFs after 4 h culture in HBSS ± Glc (20 mM) or Q (4 mM) in basal condition and after sequential addition of oligomycin (O), FCCP and antimycin/rotenone (A/R). Right: quantification of ATP-production-coupled respiration as in left. n indicates OCR measured in different wells of the same representative experiment. Box-and-whisker plots show median and minimum to maximum; data in dot and bar plots are mean ± standard deviation. Statistical analysis: Student’s unpaired two-tailed t-test or one-way ANOVA, followed by Tukey’s multiple comparisons test; NS, not significant, ****P < 0.0001. n reported in brackets. Additional replicate experiments in b, f and h are shown in Supplementary Fig. 1.
